AlexCyclistRoch

I was considering drilling an old chainring, mostly to give it that 'look'. I have access to a full machine shop, so I was going to do it on a drill press, when I thought, how much harder would it be to just make a quick CNC program on a vertical mill? As long as the same brand of ring is used, I could use it for other people's rings, if there is a market for it.

So, my question is this; how much would you pay to have your chainrings drilled, and how likely would you be to have it done?

repechage

Long ago Art Stump advised me that "Campagnolo is accurate where they need to be only" his implication was that the punched out openings in their chainrings were often off, while he had a rotary table, he reset the center between each pair of bolt holes to keep everything visually happy.
Greg Softley sells complete "drillium" rings cut from fresh stock.
I think you might find it easier to do the same from a CNC set up perspective. As the fastened work will find its own center.

CliffordK

I've thought about building a mechanical indexer for drilling rings. We'll see if I get it done.

Keep in mind your program will have to deal with different rings and teeth. Perhaps some large variations if you go with multiple brands of stock.

I rarely go for NOS, and will accept off-brands. So, I've found drilled rings for < $30, and not too much different in price from undrilled rings.

Stock sizes (42T, 52T, 53T, 54T) are more commonly drilled than other sizes.

If you are doing CNC programming, you might consider cutting your own chainrings. The amount of labor from using off the shelf rings to making your own would likely be minimal. And there is some market for unique sizes such as 144BCD x 41T.

markwesti

Being a retired machine shop owner ( CNC and conventional equipment ) I find this thread interesting . As far as a price for sure it would vary even if you could find a shop to do it . One thing you might not be considering is a fixture to hold the ring , to make that is time to make a program these days is no big deal but again time and then of course the actual machining remember you have to chamfer both sides more time . So lets just say three hours times the shop rate . When I closed my shop in 2010 my rate was $ 60 . a hour . You say you have access to a shop , so do it your self and if you have not much experience I'm sure your friend will help you get started . I have been thinking about a little drillium my self . I have been thinking about a jig holding fixture . First get a aluminum plate 1/4 thick should be ok and about the size of your chain ring . In the upper edge drill and press in two pins this will be your locating stop . The distance between the to pins will be the distance between two teeth on your ring . Now bolt this plate to a mill table put in the ring and locate where you want your first hole, lock the table.
You should be able to just hold the ring by hand but a clamp would be better drill a hole , remove ring and debur the backside repeat in till done . Next chamfer , this must be done precision no fair different diameter chamfers and no chatter marks . Sounds like some work .

Bandera

I would as I did "back when" this was a stylistic "thing" pay Zero as it was a waste of effort/$ with the risk of component failure and no performance benefit.
Gilding the Lily w/ NR components.


-Bandera

qcpmsame 

Not really very likely, but in answer to your first part of the question, I would need to see examples of their work on a part or component first. @markwesti has it summarized well in his overview of his rates for shop work when his shop was still open, I would think those are slightly higher now based on what machine work we had done for some contracts and to modify equipment.

Maybe someone here has had work done, Otis immediately comes to mind. Hope that he can comment here.

Bill

Otis

I usually charge $50-$75 for basic in-line drilling chamfered on both sides. Then go up for drill patterns above the bolt holes, cut-outs, etc. I do everything on a manual machine and it takes some time to pull 90 or so holes regardless of rotab, jigs, etc.

I have not been able to quit my day job!

markwesti

Nice work Otis !

qcpmsame 

Ain't that the whole gospel truth there!

xiaoman1 

SWEET!!!!!!!

CliffordK

Beautiful drilling above ^^

I still have to calculate where to drill and spacing, but one thing I've noticed is that the best drilling is oriented on the spider. So, if one is doing uniform spacing around the outer ring, then choose indexing in multiples of 5.

40, 45, 50, 55, 60, etc.

Doing the over/under drilling that Otis did would mean choosing multiples of 10.

Perhaps the inner rings have a little different indexing.

AlexCyclistRoch

...and yet, I see 3 tool marks at the 6 o'clock position on that second photo, on the outer ring.....

qcpmsame 

The Golden Boy 

Do you mean the Campagnolo lettering?

Class.

JohnDThompson 

The low-budget way is to index the holes using the tooth peaks:

Otis

That is the existing "Campagnolo" lettering on the ring you are seeing.

repechage

Markwesti- I had considered machining some big rings I have for a cutout pattern that is pretty rare, double sided and with cut thru ornament above the mounting holes, fixturing was the first hurdle! The orignal shows some chatter or aggressive feed rate... Fine for an original but everyone's expectation always increases with a recreation!

KonAaron Snake 

How much would I pay? When I eventually have this done, and I haven't had the right project yet, I'll pay what Otis asks.

How much would I pay someone other than drillium dude or Otis? I wouldn't...those two guys have been doing drool worthy work here for a while, and they're quality guys (even if Otis doesn't appreciate carbon ergos).

markwesti

Fixtures and set up sometimes take longer than the machining it's self . You guys are inspiring me I think I will make that drilium fixture that I was talking about in my first post , although the shop is gone (good riddance) I do have my little "closet" shop with a nifty little drillium press and a vintage Craftsman lathe .

markwesti

Countersinks can be done different ways, one way is to set the stop on the machine tool and use a countersink . However this way you run the risk of the countersink getting out of round with the hole especially if you are holding the ring by hand . Another way is to use a center drill , might be the best way as you produce the hole and countersink all at once . Another way is with this tool .
Aircraft Tool Supply 133KIT Microstop Countersink Kit with Pilot Cutters at SkyGeek.com

rootboy 

That's a nice little lathe, Markwesti. I have one of those. Need to find a new home for it but have been procrastinating.

I think there are a couple of "secrets" to the superb work shown above, by Otis. First of course is top shelf workmanship. Skill.

Second? Doing it on a machine with a highly accurate quill. ie: Bridgeport, or similar.

CliffordK

I have thought about that, and that ring doesn't look bad.

I do think drilling the spider on the SR rings unnecessarily weakens them. The NR rings have a bit more material to take out at the spider,and thus in some cases, indexing with respect to the spider works out well.

himespau 

pretty

T-Mar

I'm with JDT at one hole per tooth. If this doesn't match, then the aesthetics are thrown off. A person would have to have developed a substantial portfolio of drillium samples before I'd consider buying anything from them, regardless of the price.

Otis

How's this:

https://www.flickr.com/photos/54616231@N04/albums